1. Field of the Invention
The present invention relates to a ultrasonic bonding apparatus for performing bonding of a bonding wire and/or leads of o TAB (Tape Automated Bonding) tape to a semiconductor chip.
2. Description of Related Art
FIG. 1 shows an example of a bonding portion of a conventional ultrasonic wire bonding apparatus with a side view. The bonding portion comprises, at a one end of a horn 11, a capillary 10 having a through-hole 15 formed therein through which a bonding wire passes. A top end of the bonding wire that protrudes downwardly from a lower end opening of the through-hole 15, is wire-bonded to bonding pads of a chip (die) or internal leads of such as a ceramic package, etc. after being shaped into a sphere by an electric spark. A resonator 13 supports, at the other end of the horn 11, an ultrasonic transducer 14 with an oscillation coil. Magnetostrictive material in the transducer 14 oscillates upon a reception of a predetermined oscillation signal from the coil. This oscillation resonates with the horn 11 operating as a resonator 13 to be amplified, so that the capillary 10 vibrates horizontally at high speed.
In such conventional bonding apparatus as mentioned above, in order to vibrate the capillary 10 in a horizontal plane, ultrasonic oscillation is transformed into mechanical vibration. Therefore, the vibration frequency and the vibration waveform of the end portion of the capillary 10 are limited to those at a specific range and cannot be selected arbitrarily.
Further, since the resonance frequency is changed if the top end portion of the capillary 10 contacts with a semiconductor chip or ceramic package, etc., the vibration itself is unstable.